Apparatus for removing gases from molten metal



W. I. DURFEE & N. B.- WITTMAN. APPARATUS FOR REMOVING GASES FROM MOLTENMETAL.

I (No Model.)

1 A i No. 448,944. Patented Mar. 24, 1891.

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UNITED STATES PATENT FFlQE.

XVILLIAM F. DURFEE AND NOEL B. WITTMAN, OF BIRDSBOROUGH, PENNSYLVANIA.

APPARATUS FOR REMOVING GASES FROM MOLTEN METAL.

SPECIFICATION forming part of Letters Patent No. 448,944, dated March24, 1891.

Application filed March 17, 1890. Serial No. 344,136. (No model.)

To all whom it may concern.-

Be it known that we, WILLIAM F. DURFEE and NOEL B. WITTMAN, citizens ofthe United States, residing at Birdsborough, in the county of Berks andState of Pennsylvania, have invented certain new and useful Improvementsin Apparatus for Removing Air and Gas from Molten Metal; and we dohereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to whichit appertains to make and use the same.

Our invention has for its object the production of steel ingots whichshall be free from what are commonly known as blow-holes and similarimperfections caused by air and other gases becoming. mechanically mixedwith or occluded in the metal. We thereby produce a quality of metalwhich is especially adapted for the manufacture of heavy shafting,gun-forgings, and other articles in which it is important that the metalshould possess the greatest possible soundness and strength.

lVith these ends in view we have devised the novel apparatus forremoving air and other occluded gases from molten metal, and alsospecial mechanism operating in connec-' tion with a tilting converter,which We will now describe, referring by letters and-numbers to theaccompanying drawings, forming part of this specification, in whichFigure 1 is a longitudinal section of an ordinary Bessemer converter inoperative position; Fig. 2, a front elevation thereof; Fig. 3,-

a longitudinal section of the casting-ladle and the mold, with theexhausting-ring thereon, showing the crane which carries thecastingladle in elevation; Fig. '4, a sectional view, on an enlargedscale, of the muzzle-stopper for the converter; and Fig. 5 is asectional view, on an enlarged scale, of the top of the ingot-mold, theexhausting-ring, and the bottom of the casting-ladle.

1 denotes the converter, 2 the muzzle or mouth thereof, and A'thestopper, which we preferably construct as follows, (see Fig. 4:)

3 denotes a cylindrical cap, having a hub 4 cast on the center of itstop, the cap and hub being braced and strengthened by means of radialribs 5. i

6 denotes a yoke, to which lever 7, by which the stopper is operated, ispivoted. This yoke is provided with a shank 8, a portion of which isthreaded, as at 9, to engage an internal screw-thread in hub 4, thereduced end thereof passing through the filling of the stopper andthrougha metal washer 10, the parts of said stopper being rigidlyclamped together and held in position by means of a key driven through atransverse slot at the end of the shank, or, if preferred, bymeans of anut 11, engaging a thread at the end of the shank, as shown in Fig. 4.The filling of the stopper consists, preferably, of alternate layers ofclay (denoted by 12) and asbestus cloth, (denoted by 13.) It will ofcourse be understood that any suitable or convenient number of layers ofclayand asbestus cloth maybe used in the stopper, and that felt or otherkinds of cloth may be substituted for asbestus cloth, if preferred, theobject being to provide a filling that will be refractory and air-tightand that will yield and cohere while being compressed.

17 denotes the end of a chain by which lever 7 is suspended from the armof a crane or any other suitable means for supporting and manipulatingsaid lever and its attachments.

18 denotes a hook upon the converter under which lever 7 is swung andwhich acts as a fulcrum for said lever, as will be more fully explained.

The converter is provided with trunnions 14 and 15, one of which, thelatter, as shown in the drawings, is made hollow. These trunnions areadapted to turn in suitable boxes 16 on the tops of the standards. Theblast is supplied to the converter by a suitable engine (not shown)through a pipe 19, the hollow'trunnion 15, and a pipe 20, leading fromsaid trunnion to the tuyere-box 21, from whence the blast passes intothe converter through tuyeres 22. It will of course be understood thatduring that part of the ordinary process known as the blow themuzzle-stopper is removed from the mouth of the con-- verter. At thisstage of the process the converter is turned down and the spiegeleisenor other recarburizing material is added to the metal in the converter,or, in case the metal therein is so constituted as to require no suchaddition, the other steps of the process are proceeded with. At theother end of lever 7 is pivoted an internally-threaded tube 23, which isengaged by a screw 24, having a hand-wheel 25 for convenience inoperation. The lower end of this screw rests in a step 26, which issecured to a suitable platform 27. As soon as the metal in the converteris ready for the application of the exhausting process the communicationwith the blast-engine is cut off by closing valve 28 in pipe 19, thestopper is placed over the mouth of the converter, and lever 7 is passedunder hook 18. As soon as the stopper is properly adjusted to the mouthand the lever engaged by the hook the lower end of screw 24 is placed inthe step 26 and the hand-wheel is rotated to raise the outer end of thelever and force the stopper tightly against the mouth of the converter,thereby effectually closing it. As soon as the mouth of the converter isclosed a valve 29 is opened in a pipe 30, which leads directly from thehollow trunnion (see Fig. 2) to a suitable vacuum-chamber or exhaustedreceiver 31, said chamber being indicated at the right in Fig. 2. Assoon as valve 29 is opened the air and heated gases within the converterand the metal contained therein will, by reason of the diminishedpressure on the surface of said metal, escape rapidly and completelytherefrom and pass through the tuyeres, the tuyere-box, pipe 20, thehollow trunnion, and pipe 30 into the vacuum-chamber, it beingunderstood, of course, that external air and gases are prevented fromentering the vacuum-chamber by the closing of the mouth of the converterand the valve in the pipe from the blast-engine. As soon as the air andgases have escaped from the converter and the metal contained thereininto the vacuum-chamber, valve 29 in pipe 30 is closed, thus cutting offall communication between the vacuum-chamber and the converter.Hand-wheel 25 is then turned backward, so as to lower the outer end oflever 7 and permit said lever to be removed from under the hook, leavingsaid lever suspended by chain 17. Valve 28 in the blast-pipe is thenopened, which admits air to the interior of the converter through pipe20, the tuyere-box, tuyeres, &c., thus counter-balancing the pressure ofthe external air on the stopper and permitting it to be swung away fromthe converter by means of the suspending-chain, after which theconverter is turned down in the usual manner and its contents pouredthrough the mouth into a castin -ladle 32, which is attached to the arm33 of a hydraulic or other crane so constructed that the casting-ladlecan be raised or lowered at pleasure, and also made to swing in acomplete circle whose center is the post 34 of the crane. Thecasting-ladle is provided with a plug or stopper 35, which closes atap-hole 36 in the bottom thereof. This stopper is carried by an arm 37,which curves over the top of the casting-ladle and passes through guides38 on the outer side thereof. A lug 39 is provided on arm 37,

which is adapted to be engaged by a suitable bar or lever (not shown)when it is desired to raise the stopper. On the under side of thecasting-ladle and surrounding the tap-hole is rigidly secured a metallicring 40.

41 denotes an ingot-mold of any ordinary or preferred construction.Before permitting the metal to pass from the casting-ladle into theingot-mold we interpose between ring 40 and the ingot-mold anexhausting-ring B, which we preferably construct as follows, (see Fig.5:) In the upper and lower faces of this ring are dovetail grooves 42,which are filled with alternating layers of clay and asbestus cloth,denoted, respectively, by 12 and 13. The exact number of layers is ofcourse not of the essence of our invention. We use any number that maybe found most convenient, the special object being the yieldingrefractory air-tight coherence of the filling under compression,as willbe more fully explained.

43 denotes a pipe leading out from one side of the exhausting-ring. Thispipe is made of suflicient strength to support the weight of the ringand is kept at its proper position by arms 44, which extend downwardfrom the arm of the crane. The lower ends of these arms are providedwith elongated openings, through which pipe 43 passes, thus permittingsaid pipe to be moved vertically, longitudinally, and axially, butretaining it in position against lateral movement.

45 denotes joints in pipe 43 similar to ordinary gas-pipe joints, whichpermit the pipe to be carried in any direction, in order to connect itwith a chamber46 on the top of cranepost 34. This chamber has at its topa stuffing-box 47, through which passes a pipe 48, the same size as pipe43, which leads to a vacuum-chamber. This vacuum-chamber may be chamber31, a portion of which is shown in Fig. 2, and which is described asconnected with the converter, or a special vacu u m-chamber may beprovided, if preferred. Pipe 43 is provided with a valve 49, by which itis opened and closed, and with a handle 50, by which it may be movedlongitudinally or vertically or axially, as may berequired. hen it isdesired to tap the metal in the castingladle into an ingot-mold placedin proper position to receive it, the exhausting-ring B is placed uponthe top of the mold, as clearly shown in Fig. 5, and the casting-ladleis lowered upon it, ring 40 upon the under side thereof coming incontact with the filling in the upper dovetail groove in said ring, andthe filling in the lower dovetail groove being forced against the top ofthe ingot-mold, as clearly shown in Figs. 3 and 5.

In practice the casting-ladle is lowered until both the upper and lowerfillings in the exhausting-ring are somewhat compressed by the weight ofthe ladle and its contents, so as to make practically air-tight jointsbetween ring 40 and the upper filling and between the top of theingot-mold and the lower filling. As soon as the casting-ladle has beenlowered sufficiently to insure perfectly-tight joints its downwardmovement is stopped and valve 49 in pipe 43 is opened, which permits theair in the ingot-mold to pass through said pipe into the vacuum-chamberor exhausted receiver with which said pipe is connected. Theladle-stopper 35 is then raised by means of a suitable bar orleveracting on the lug 39, which permits the molten metal in thecasting-ladle to pass out at the tap-hole and through theexhausting-ring into the ingotmold, which has previously been exhaustedof air, as described.

\Ve find in practice that by running a stream of molten metal into amold from which the air has been exhausted all the air and otheroccluded gases in said molten metal are caused to pass out therefromwhile the stream is descending and to pass through pipe 43 into the vacuum-chamber. It is not necessary for the carrying out of the exhaustingprocess that the vacuum in the vacuum-chamber or exhausted receivershould be perfect; but we preferably make it as nearly so as ispracticable.

lVe wish it distinctly understood that we do not confine our inventionto use in connection with the particular metal-holding devices describedherein.

WVe have in our application, Serial No. 358,126, filed July9, 1890, madeclaim to the closing-ring and apparatus shown in Figs. 3 and 5.

Having thus described our invention, we claim- 1. A muzzle-stopper forconverters, consisting of a cylindrical cap having a hub, infusibleyielding material-for example, alternate layers of clay and asbestuscloth-within the cap and exposed and adapted to rest directly upon theedge of the mouth of the converter,

a metal washer on the outerside of the filling, and a shank passingthrough said washer, the cap, and the filling, whereby said parts arecompressed together, as and for the purpose set forth.

2. The combination, with a converter having a hollow trunnion, asuitable stopper, a lever by which said stopper is carried, a chain bywhich said lever is suspended, and a hook 18 to engage said lever, of athreaded sleeve at the other end of said lever, a screw engaging saidsleeve and acting to close the stopper against the converter, a fixedstop for said screw,a vacuum-chamber, pipes 19, 20, and 30, connectingthe converter with an air forcing or blast device and with saidvacuumchamber, and suitable valves in said pipes, substantially asdescribed.

3. A muzzle-stopper for converters, consisting of a cylindrical caphaving ahub, layers of compressible material within the cap and exposedand adapted to rest directly upon the edge of the mouth of theconverter, a metal washer on the outer side of the filling, and a shankpassing through said washer, the cap, and the filling, whereby saidparts are compressed together, as and for the purpose set forth.

4. In combination with a vessel for receiving molten metal, a yieldingclosing device or valve comprising a rigid backing or support andalternate layers of clay and asbestus exposed and adapted to rest on theedge of the mouth of the vessel, substantially as set forth.

In testimony whereof we affix our signatures in presence of twowitnesses.

WILLIAM F. DURFEE. NOEL B. WITTMAN.

Witnesses:

LESLIE GRISOOM, ALBERT FRITZ.

